| 摘要 |
PURPOSE:To detect the inclination of an objective plane highly precisely without any influence of surface reflection characteristics of the objective plane by radiating light images of slits which cross each other at right angles, and extracting a couple of light images from the output signal of a two-dimensional image pickup element. CONSTITUTION:The two-dimensional image pickup element 10 has an axis of photodetection crossing perpendicularly the axis of projection of a light source 9a which converts a converged light beam into a slit-shaped light image and radiates it, and a light source 9b radiates the light image of slits crossing each other at right angles at an intersection. A means 15 judges the two-dimensional inclination of the plane of the body 13 to be detected from position information on the detected slit couple obtained through a means 14 which extracts the light image couple from the output signal of the element 10, and the element 10. Therefore, the angle of inclination of the objective plate is detected precisely without any influence of the reflection characteristics of the plane of the object 13. |
